ATLANTA (AP) — An American doctor infected with Ebola while working in Liberia indicated Friday he’s getting stronger every day, and the husband of a second aid worker with the deadly virus said his wife also seems to be improving.

Dr. Kent Brantly and Nancy Writebol are being treated in an isolation unit in Atlanta. The two were infected while working at a missionary clinic outside Liberia’s capital.

“I am writing this update from my isolation room at Emory University Hospital, where the doctors and nurses are providing the very best care possible,” Brantly said in a statement put out by Samaritan’s Purse, the aid organization he was working with in Africa. “I am growing stronger every day, and I thank God for His mercy as I have wrestled with this terrible disease.”

Writebol’s husband, David, who remains in Liberia, told reporters Friday in a phone call that while he hasn’t spoken directly to his wife’s doctors, his sons told him she’s showing some improvement.

“I don’t believe we could say she’s in the clear,” David Writebol said. “I would say she’s in very good hands and is being well attended to.”

Few specific details have been released about their conditions. Todd Shearer with Samaritan’s Purse said Brantly’s family has asked that no condition information be given out. The president of SIM USA, the group Writebol was working for, referred questions to Emory, which has declined comment, citing patient privacy.

Brantly and Writebol were given doses of an experimental treatment before leaving Liberia. David Writebol said his wife has received another dose since arriving in Atlanta.

It wasn’t immediately clear whether Brantly had also received another round of the medication in Atlanta. The treatment, which aims to boost the immune system’s efforts to fight off Ebola, is still in development and hasn’t been tested in humans.